1. Field of the Invention
The present invention relates to a glass tube cutting device configured to cut a continuously travelling continuous glass tube formed by tube pulling typically using the Danner method at a predetermined length and a cutting method for same.
2. Description of Related Art
Conventionally, glass tubes used for luminescent lamps, medicinal containers such as ampoules and vials, back light for liquid crystal panels are generally produced by the Danner method (For instance, see JP 07-172852 A).
As shown in FIG. 8, in a muffle furnace 100, melt glass M which flows down is wound around an outer peripheral surface of a sleeve 110 for continuously rotating to be formed into a cylindrical shape and the cylindrically-shaped melt glass is continuously drawn by a tube puller 200 disposed outside the muffle furnace 100 while blowing air A1 into an inner side of the cylindrically-shaped melt glass to form a continuous glass tube G1 by tube pulling. Subsequently, keeping the continuous glass tube G1 continuously travelling, a cutting blade 310 of a glass tube cutting device 300 is caused to be intermittently in contact with an outer peripheral surface of the continuous glass tube G1 to obtain a plurality of cut-off glass tubes G2 by cutting the continuous glass tube G1 at a predetermined length. Both ends of the plurality of cut-off glass tubes G2 are re-cut and are glazing treated while conveying the obtained cut-off glass tubes G2 by a conveyor 400 to produce a finished glass tube product.
Conventionally, devices described in JP 2007-331994 A, JP 09-067136 A, and JP-UM-02-087034 A are each known as a glass tube cutting device configured to cut a continuous glass tube that continuously travels. Such glass tube cutting devices are each configured to produce scratches by contacting a cutting blade with an outer peripheral surface of the continuous glass tube and impose thermal shock at the same time to cut the continuous glass tube.
However, conventional glass tube cutting devices were each configured to simply contact a cutting blade with a continuous glass tube, so that as shown in FIG. 9, there was a disadvantage of deterioration in purity of a cut-off glass tubes G2 because finely-crushed glass P generated at the time of cutting was blown into an inner side of a cut-off glass tube G2 from a rear end opening B2 of the cut-off glass tube G2 by air A1 coming out of a tip end opening F1 of the continuous glass tube G1, which resulted in adhesion of finely-crushed glass P to an inner surface of the glass tube. Since such a disadvantage in which finely-crushed glass P was adhered to the inner surface of the glass tube was particularly important for glass tubes used for medicinal containers such as ampoules and vials, particular careful cleansing work inside the glass tubes after cutting treatment had to be performed.